TUNGSTEN: Hard and Gray with a High Melting Point

Word Origin and History: Tungsten originates from two Swedish words, tung sten, which means heavy stone. The element was discovered by Spanish chemists Juan José and Fausto Elhuyar. In 1783, they effectively isolated the element from an acid (called tungstic acid then) obtained from wolframite (a mineral made of the element, iron, manganese and oxygen) by reducing the acid with charcoal. Until now, the element has been extracted from mineral ores such as scheelite and wolframite utilizing the same method of its discoverers.

It had remained as a rare element for more than half a century until Oxland successfully obtained a patent for its production and related compounds tungstic acid and sodium tungstate. A few years later, in 1857, Oxland sought a patent for its alloys with iron. These marked the early stages of the element finding its way to having important industrial applications. The most common and known application of the element is the filament used in incandescent light bulbs.

Its name was previously that of another mineral, scheelite, which also contained the element along with calcium and oxygen. The first use of the term is attributed to A.F. Cronstedt who applied it to the said mineral in 1755. To distinguish the element from the mineral compound, naming formalizations were done.

Health Hazards, Preventive Measures, Remedies and Treatment:

In trace amounts, people are exposed to the element primarily through the soil they touch and the water they drink. The metal is considered toxicologically inert and thus does not pose health risks in trace amounts.

However, workers involved in occupations dealing with it directly are relatively more exposed to the metal and its related compounds. Undoubtedly, this exposure poses health risks.

Pure metal
The metal’s dust may cause irritation of the eye, skin and respiratory tract (e.g. nose and throat). In case of inhalation, the victim must be brought to a location away from the source and breathing must be assisted as necessary. Loosening clothing should be done. Acute exposure can be characterized by sneezing and coughing.

Severe exposure can result to choking, unconsciousness and possibly, death. Chronic exposure may result to the worst scenario of pulmonary fibrosis or scarring of lung tissues due to the abrasive nature of the metal. This is normally accompanied by difficulty in breathing.

In case of skin contact and irritation, which is characterized by scaling, reddening and itching, the affected area must be washed with soap and water for 15 minutes and contaminated clothing must be removed. In case of eye irritation, one has to flush the affected eyes with water for 15 minutes. Contact lenses must be removed and no ointments should be applied. Severe exposure may cause blindness.

In case of ingestion, vomiting must be induced in the victim and drinking of substantial amount of water should be done. Ingesting a substantial amount of the metal can cause nausea, seizures, hypocalcaemia (low level of serum calcium) or even kidney failure.

In any case, medical assistance must be sought as the symptoms resemble those of exposure to other metals. Aside from this, periodic and regular medical examination is strongly needed for people who are regularly exposed to the metal’s dust or powder form.

Currently, the metal is not considered or even suspected to be a cancer-causing agent by respected health and safety organizations such as OSHA (Occupational Health and Safety Administration), NTP (National Toxicology Program) and IARC (International Agency for Research on Cancer). Nevertheless, working with the heavy metal (e.g. grinding, welding) demands use of safety goggles or glasses, gloves and respirator when dust is expected to be produced. It also requires proper ventilation.

The compound WC
WC (Tungsten carbide [chemical formula: WC] is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms) shares the metal’s health hazards. Acute and chronic exposure to it also results to irritation and possibly pulmonary fibrosis or emphysema (long-term, progressive disease of the lungs that primarily causes shortness of breath). The same remedies and preventive measures apply.

Similarly, working with the compound requires appropriate PPEs (personal protective equipment) such as goggles and full body protective clothing. Adequate ventilation must also be ensured when working with the compound.

Fire and Explosion Hazard and Preventive Measures
Accumulated dust of the metal or the compound WC may ignite if exposed to ignition sources. To prevent fire, handlers must exclude oxygen by putting inert powder such as limestone or dry sand. On the other hand, wrought (formed by work or labor; as wrought iron) products do not quickly burn and need less attention.

Regular and effective housekeeping must be done to prevent dust accumulation. This includes the use of vacuum cleaner and wet clean-up. In addition to this, the container must be kept dry and away from heat or heat sources.

General, Physical and Chemical Characteristics/ Properties:
Tungsten usually occurs in minerals in soil rather than as a pure substance. It is one of the transition metals in the periodic table. The lustrous metal’s phase is solid and its color is gray or grayish-white; and it has no odor.

Among metals, it possesses very desirable characteristics such as having the highest tensile strength above 1650 °C, lowest vapor pressure among metals and highest melting points also among metals. Pure tungsten resists redox reaction, as well as acidic and alkalinic reactions.

Other facts about the metal are the following:
Symbol: W (from wolfram derived from wolf rham or wolf cream referring to the fact that extracting wolframite consumed too much tin)
Atomic Number/ Atomic Mass: 74
Atomic Weight: 183.84
Melting Point: 3410 °C
Boiling Point: 5900 °C
Specific Gravity (water = 1):  19.3

Common Compounds and Applications:

Tungsten carbide (WC) in hard materials
It is used in creating cutting tools such as drills, saws, milling and knives used in intensive industries such as petroleum, construction, woodworking, mining and metalworking. The compound also has applications in jewelry.

Alloys and Electronics
Due to the desirable properties mentioned previously, specifically its very high melting point, the metal is used in various applications requiring or involving high temperature environment such as

• high speed steels (a special tool) exposed to high temperatures due to immense friction

• rocket nozzles exposed to high temperatures during rocket launches and atmospheric entry and exit

• light bulbs and cathode ray tubes

Other known compounds are WCl6 (a hexachloride), WS2 (a sulphide) and WO2 (an oxide). Other known applications are in paints, X-ray targets and salts for tanning.

[The information contained in this article is believed to be reliable. I have taken every precaution to verify its accuracy; I am not a medical professional and make no warranties, representations or guarantees of any kind as to its accuracy. Medical knowledge is in a constant state of change, and what I have written here may be out of date by the time you read it. The information that I have provided here is for informational purposes only and not for use in diagnosing any condition that you may or may not have. Always consult with you doctor before treating yourself.]